This invention relates to tire monitoring apparatus and the like.
A tire pressure monitoring device is disclosed in U.S. Pat. No. 4,137,520. The device comprises a wire strain gauge employed as a pressure transducer which is connected to a telemetering circuit disposed on an integrated circuit chip. Also disclosed is circuitry for encoding the telemetering signals to discriminate one tire from another.
U.S. Pat. No. 4,237,728 discloses a tire pressure transducer/telemetering system where the transducer is mechanically activated and may include a piezoelectric crystal or the like to detect either under or over inflated tire conditions. Each time an abnormal condition is sensed, a pulse is generated. After a predetermined number has been sensed in a given period of time, an alarm signal is sent.
U.S. Pat. No. 4,160,234 discloses a tire pressure monitoring apparatus including a charge storage release circuit which produces a pulsed abnormal condition signal. The charge portion of the circuit stores the transducer signal until a predetermined signal level is reached, at which time it is transmitted.
An article in "Electronics" magazine, Aug. 11, 1983, entitled "Chip Senses Heat, Pressure" describes a pressure-temperature transducer with associated signal processing circuitry disposed on an integrated circuit chip.
Other patents of interest are U.S. Pat. Nos. 4,048,614; 4,072,927; 4,263,579; 4,300,119; 4,300,120 and 4,311,984.
All of the above prior art references are submitted herewith and it is requested they be made of record.